PROTOZOA 143 



Should the cultivation of more than one generation be desired, the leucocyte 

 upper layer must be carefully pipetted off, as the leucocytes immediately destroy the 

 merozoites. Only the parasites within red cells escape phagocytosis. Sexual 

 parasites are much more resistant, and the authors think they observed partheno- 

 genesis The temperature should be from 40 to 41 and strict anaerobic conditions 

 observed. ^Estivo-autumnal organisms are more resistant than benign tertian ones. 

 Dextrose seems to be an essential for the development of the parasites. 



Noguchi first cultivated spirochsetes; others have extended and modified his 

 work. If a few drops of blood containing spirochaetes is dropped into sterile ascitic 

 fluid, hydrocele fluid, or blood plasma, to which a piece of sterile tissue, such as 

 rabbit's kidney, is added, the spirochaetes multiply. The test tube should contain 

 about 15 ccm. of culture fluid. It is advantageous to cover the fluid with sterile 

 paraffin oil. 



